Method for solvent scouring knit webs and the like

ABSTRACT

A running web of easily stretchable material such as knit goods or the like is solvent scoured on a continuous basis by means of a plurality of conveyor belts which deliver the web from a solvent spray station in an enclosure through a drying stage, the longitudinal tension in the fabric itself being employed to control the speed of the conveyors. The web is transferred from one conveyor to the next in a relaxed condition and in the drying stage steam coils are employed to heat the enclosed atmosphere whereby the vaporized solvent itself serves as a drying agent in flashing off liquid solvent in the web.

United States Patent Holm Oct. 2, 1973 METHOD FOR SOLVENT SCOURING KNITWEBS AND THE LIKE Primary Examiner-William I. Price [76] Inventor:William J. l-lolm, 26 East Ln., Oates Springfield, Vt. [22] Filed: Dec.13, 1971 ABSTRACT [21] A N() 207,605 A running web of easily stretchablematerial such as knit goods or the like is solvent scoured on a continu-Related Apphcatmn Data ous basis by means of a plurality of conveyorbelts Division of 381,497, 1969, which deliver the web from a solventspray station in an 3,640,099 enclosure through a drying stage, thelongitudinal tension in the fabric itself being employed to control the[52] US. Cl. 8/151 Speed of the conveyors. The web is transferred from[51] it. Cl. B056 3/132 one conveyor to the next in a relaxed conditionand in [58] Field of Search 8/151; 68/19.], 205 R, the drying Stagesteam n are employed to heat the 68/22 44 enclosed atmosphere wherebythe vaporized solvent itself serves as a drying agent in flashing offliquid sol- [56] References Cited FOREIGN PATENTS OR APPLICATIONS ventin the web.

1 Claim, 1 Drawing Figure 647,625 8/1964 Belgium 68/l9.1

12 10 a g u q as v 54 5 METHOD FOR SOLVENT SCOURING KNIT WEBS AND THELIKE This is a division, of application Ser. No. 881,497, filed Dec. 2,1969 now U.S. Pat. No. 3,640,099.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates generally to the production of textile webs and moreparticularly is directed towards a novel method for solvent scouringknit goods or the like on a continuous basis without distorting thefabric.

2. History of the Prior Art In the production of textiles it is thepractice to scour or otherwise treat the material to remove variousimpurities from the web. Because of the high stretch-strain ratio ofknit materials and other fragile materials, there has been nosatisfactory means available for processing materials of this type on acontinuous basis. Heretofore, the practice has been to scour material ofthis type on a batch basis which is quite slow and inefficient.

Accordingly, it is an object of the present invention to provide a newmethod for scouring or otherwise treating on a continuous basis fragileweb materials such as knit goods or the like without distorting the web.

SUMMARY OF THE INVENTION This invention features a novel method ofprocessing a running web of knit material or the like on a continuousbasis, comprising the steps of supporting the running web in an openwidth relaxed condition while spraying a solvent over the web. The webis then squeezed to remove excess solvent and transferred to anotherconveyor in an enclosure wherein the solvent is vaporized through themedium of a heated vapor atmosphere to dry the web.

This invention also features an apparatus for continuously scouringfragile fabric webs comprising a plurality of variable speed conveyorsarranged to transfer the web from one to another in a relaxed conditionand fully supported throughout and within an enclosure wherein'the webis first washed with a solvent and then dried by a heated atmosphereemploying heating elments disposed in proximity to the running web. Acondensate system is provided for recovering the vaporized solvent.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view in sideelevation of an apparatus made according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to thedrawings, the reference character generally indicates an enclosure inthe form of a housing having an inlet slot 12 at the left-hand endthereof and an exit slot 14 at the right-hand end thereof. The apparatusis generally organized into three main sections namely, a wet-outsection in the upper left-hand portion thereof, a drying section in therighthand portion thereof and a condensate section in the lowerleft-hand portion thereof.

The wet-out section includes an endless conveyor belt 16 supported anddriven by means of rolls [8 and 20 operating in conjunction with atensioning roller 22. The belt and rollers are arranged to provide ahorizontal upper reach 24, the left-hand end of which is located belowthe entrance slot 12 in position to pick up a web 26 delivered in openwidth form through the slot, downwardly onto the conveyor for movementto the right through the wet-out section. Disposed transversely abovethe horizontal upper reach 24 of the conveyor and the web 26 are spacedspray nozzles 28 adapted to spray solvent or the like down over the webto wash out various impurities. In order to provide an optimum washingaction, it is desirable that a perforate conveyor belt 16 be employed topermit the solvent to flow through the web and belt. The solvent drainsfrom the web and belt down onto an inclined baffle 30 which directs thesolvent into a drain 32, preferably provided with a flock screen 34 forfiltering the solvent before it drains through a solvent seal into astill 36. The still is provided with cooling coils 38 in its upperportion for condensing the vapor from solvent evaporated by heatingcoils 40 in its lower portion. Adjacent to the still 36 is a storagetank 42 for clean solvent, the tank connecting with a water separator 44which also receives condensate draining from the cooling portion of thestill by means of a drain line 46. In addition, the water separator alsocollects the condensate from the drying portion of the apparatus.Suitable pumps (not shown) are provided for delivering clean solventfrom the storage tank to the spray nozzles 28.

As the web 26 leaves the conveyor 16 and before it enters into the biteof a pair of nip rollers 48 and 50, it engages a pivoted feeler 52 whichsenses the tension on the web and by means of a switch 54, whichoperates in response to the movement of the feeler 52, controls thespeed of variable speed motors which drive either or both of theconveyor rollers 18 and 20. The arrangement insures that the web 26 doesnot become too slack or too tight and provides a direct and immediatecontrol over the web tension by controlling the speed of the conveyorbelt 16 independently of any other conveyor in the system.

From the nip rolls 48 and the web 26 is delivered into the dryingsection of the apparatus and is guided down onto the uppermost of a bankof stacked conveyors, each comprised of a belt 52, rollers 54 and 56, atleast one of which is driven, and a tensioning roller 58. The severalconveyors are arranged in staggered relation with horizontal upperreaches positioned to receive the web as it travels from one conveyordownwardly to the next and thence out through the exit slot 14. At thestart of each conveyor where the web is delivered onto the upper reachof the belt, a web feeler is provided similar to the feeler 52 describedabove and each feeler is adapted to control a switch or other device bywhich variable speed motors driving each of the drying conveyors may beregulated independently of one another. The feelers 60 and 52 insurethat the web does not become longitudinally stretched by controlling thespeed of the conveyors and also insure that the web does not become tooslack so as to fold or otherwise become distorted.

Disposed above the upper horizontal reach of each drying conveyor 52 areheating elements 64, typically steam coils, extending over with width ofthe web and co-extensive therewith. The steam coils 64 serve to heat theatmosphere within the housing, the atmosphere being comprised primarilyof vaporized solvent. The vaporized solvent is heated by the steam coilsand the heated vapor itself is sufficent to cause the liquid solvent inthe web to flash off into vapor, leaving the web free of the solvent sothat by the time it is discharged from the tank the web is in a clean,dry condition.

A final tension feeler 66 is located at the discharge end of thelowermost conveyor prior to the exit slot 14 to control the speed of thetakeup roll located outside the housing. Located at the base of thedrying section are cooling coils 68 disposed directly above a waterjacket 70 which is slightly inclined to deliver condensate into thewater separator 44. In practice, the temperature of the atmospherewithin the drying section can be maintained at a relatively low leveland a range of l40l60 F. is sufficient for most common types of scouringsolvents to flash off into vapor.

It will be appreciated that the tension in the web itself controls thevarious conveyors individually to insure maintaining the web in asubstantially relaxed condi tion as it is processed. While the apparatushas been described as employing pivoted sensing feelers, various othertension sensing means may be employed, such as photoelectric systems forexample, by which the sag in the material may be sensed and controlledby speeding up or slowing down individual conveyors.

Having thus described the invention what I claim and desire to obtain byLetters Patent of the United States l. The method of processing a web ofknit material or the like with a liquid medium, comprising the steps ofa. carrying said web fully supported throughout in an open width relaxedcondition along a longitudinal and substantially horizontal path,

b. spraying said liquid over said web along a first portion of saidpath,

c. forcibly removing part of the liquid from said web along a secondportion of said path,

d. heating the atmosphere along a third portion of said path to atemperature sufficient to vaporize the remaining portion of liquid insaid web.

